1. Field of the Invention
The present invention relates to a bipolar cutter which is inserted into a body of a living thing and which cuts a living tissue as a cutting target in the living body and cauterizes a cutting section of the living tissue by using a pair of electrodes.
2. Description of the Related Art
Conventionally, there is known a bipolar cutter including a pair of jaws which can open and close and which is electrically conductive. After being inserted into the body of the living thing, the pair of jaws is opened to nip the living tissue as the cutting target in the body of the living thing therebetween. Then, the pair of jaws is closed while an electric current is applied thereto, whereby the living tissue nipped by the jaws is cut and its cut surface is cauterized.
Conventionally, there is also known a bipolar cutter including a pair of electrodes which are separated from each other with a predetermined distance and a cutting tool. The pair of electrodes is inserted into a body of a living thing and nips a living tissue as a cutting target in the body of the living thing therebetween. Then, while an electric current is applied to the pair of electrodes, the living tissue nipped between the electrodes is cut by using the cutting tool, whereby a cut surface of the living tissue is cauterized.
In these conventional bipolar cutters, the living tissue as the cutting target cannot be cut by simply applying an electric current to the pair of jaws or the pair of electrodes while the jaws or electrodes are nipping the living tissue as the cutting target. In order to cut the living tissue as the cutting target, a closing operation of the pair of jaws or an operation of the cutting tool is required.
Jpn. Pat. Appln. KOKAI Publication No. 2003-199766 discloses a bipolar cutter, in which a V-shaped notch is formed in a front-end portion of an insertion unit introduced in a body of a living thing and a pair of electrodes is disposed at an inner end of the V-shaped notch. One of contact areas of the pair of electrodes exposed at the inner end is set smaller than the other contact area. In the conventional bipolar cutter disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2003-199766, the inner end of the notch of the insertion unit introduced in the living body is pressed against a living tissue of a cutting target in the living body, whereby the living tissue is cut by one electrode having the smaller contact area and at the same time a living tissue around the cut surface is cauterized by the other electrode having the larger contact area.
In the conventional bipolar cutter described in the above described Publication, only a living tissue having a size within a range of the V-shaped notch size can be cut because the size of the V-shaped notch is fixed.